The present invention concerns a power supply apparatus intended in particular to be used in an aircraft. It concerns more particularly a power supply apparatus of the type comprising:
an input for receiving an input electric current;
first and second outputs for providing first and second electric power supply currents each having specific characteristics; and
means for conversion of the electric current connected between said input and said first and second outputs.
It is nowadays necessary in aircraft cabins to supply electrical energy to different operational members which are available to passengers. Those operational members are formed for example by video screens, lamps, power supply sockets for portable computers as well as electrical actuators which are fitted in the seats in order to ensure independent displacement of different movable components of the seat.
Those operational members are supplied with power from the electric power distribution system of the aircraft, which conventionally delivers an alternating current at 115 volts, at a frequency of 400 Hz.
Numerous operational members require a power supply with alternating current at 110 volts, at a frequency of 60 Hz for their operation. On the other hand, for safety reasons, other operational members such as the motors of the actuators which are fitted in the seats are direct-current devices. Their power supply voltage is generally 12 or 24 volts.
It is known to connect to the electric power distribution system installed in the aircraft a converter for implementing conversion of the alternating current into direct current. To supply alternating current to the operational members requiring such a power supply another converter is used. That provides for conversion of the distributed alternating current into an alternating current of different voltage and frequency.
Thus, the known solution involves using a plurality of converters each incorporating a transformer. Those converters are each connected to the electric power distribution system of the aircraft. That power supply architecture is relatively bulky and increases the total weight involved in the power supply.
The object of the invention is to propose a power supply apparatus of reduced bulk and weight, which makes it possible to supply power to a plurality of types of operational members from electric currents of different characteristics.
For that purpose the invention concerns a power supply apparatus of the above-mentioned type, in which said conversion means comprise a transformer comprising a primary winding supplied by the input electric current and first and second secondary windings respectively feeding the first and second outputs by way of first and second shaping circuits, the primary winding and the first and second secondary windings being disposed on the same magnetic circuit, the first shaping circuit comprising regulating means adapted to act on the electric current supplying the primary winding, which regulating means are adapted to ensure regulation in dependence on a signal from the first shaping circuit, and the second shaping circuit comprising autonomous means for regulation of the current produced by the second output, said second shaping circuit being adapted to produce an alternating current; and the second shaping circuit comprising a rectification stage and, at the output of said rectification stage, means for modifying the voltage in accordance with a variable division ratio:
In accordance with particular embodiments the apparatus comprises one or more of the following features:
said first shaping circuit is adapted to produce a direct current;
said means for modifying the voltage in accordance with a variable division ratio comprise a regulator for the output voltage of said means for modifying the voltage in accordance with a variable division ratio and means for controlling said regulator on the basis of a variable control voltage;
said means for controlling a variable control voltage comprise a variable-ratio voltage divider bridge connected at the output of said means for modifying the voltage in accordance with a variable division ratio;
said second shaping circuit comprises at the output of said means for modifying the voltage in accordance with a variable division ratio an inverter bridge controlled at a predetermined frequency; and
said means for modifying the voltage in accordance with a variable division ratio are adapted to produce a periodic signal of a frequency double the alternating current produced at the output of the second shaping circuit.
The invention also relates to a method of converting an electric current from an input of a power supply apparatus receiving an input electric current, to first and second output electric currents each having specific characteristics.